Rotary Valve Internal Combustion Engine

ABSTRACT

A rotary cylinder valve, reciprocating piston, internal combustion engine, has a crankshaft  2  and a transmission drive to drivingly connect the crankshaft  2  to the rotary cylinder  1 , the axis of the cylinder  1  being at an angle to the axis of the crankshaft  2 , the transmission drive including a gear train having a first gear  4  rotationally fast on the crankshaft  2 , a second gear  8  rotationally fast on the rotary cylinder  1  and an idler gear  5  to transmit drive between the first and second gears.

The present invention relates to a rotary cylinder valve reciprocating piston internal combustion engine having a cylinder within which the piston reciprocates, the cylinder being rotatable about its longitudinal axis in a cylindrical bore of a valve housing, the cylinder having a closed end which defines a combustion chamber between the closed end and the piston and a valve port in fluid communication with the combustion chamber, the valve housing having an inlet port and an outlet port adapted to be successively aligned with said valve port during rotation of the cylinder in the housing to enable fluid to flow respectively into and out of the combustion chamber.

Such rotating cylinder valve engines are known, for example from PCT/GB 01/04304 and PCT/GB 2003/002136.

The present invention seeks to provide improved forms of such engines.

According to one aspect of the present invention there is provided a rotary cylinder valve, reciprocating piston, internal combustion engine, having a crankshaft and a transmission drive to drivingly connect the crankshaft to the rotary cylinder, the axis of the cylinder being at an angle to the axis of the crankshaft, the transmission drive including a gear train having a first gear rotationally fast on the crankshaft, a second gear rotationally fast on the rotary cylinder and an idler gear to transmit drive between the first and second gears.

Preferably, said angle is a right angle.

In a preferred embodiment, a balance weight is integrally formed in the idler gear, the balance weight thereby contra-rotating relative to the direction of rotation of the crankshaft. In an alternative form, a balance weight is secured to the idler gear in a rotationally fast manner the balance weight thereby contra-rotating relative to the direction of rotation of the crankshaft.

The first gear and the idler gear preferably have straight cut, helical cut or bevel gear teeth.

In one embodiment, the idler gear has a further gear rotationally fast thereto, the further gear comprising an axially extending face gear adapted to mesh with a spur gear on the rotary cylinder. In one form, the spur gear is formed in the rotary cylinder. In another form, the spur gear is a gear ring mounted, preferably by shrinking, on the rotary cylinder.

In another embodiment, the idler gear has a further gear rotationally fast thereto, the further gear comprising a bevel gear adapted to mesh with a bevel gear on the rotary cylinder. The bevel gear may be formed in the rotary cylinder or may be a gear ring mounted on the rotary cylinder, in which case, the gear ring may be shrunk on to the rotary cylinder.

The face gear of the idler gear may be adjustable axially towards and away from the spur gear on the rotary cylinder. The gear interface meshing between the idler gear and the rotary cylinder is preferably such that the cylinder is movable relative to the idler gear in a plane at right angles to the axis of rotation of the idler gear whilst still maintaining said meshing. This enables the cylinder to be moved axially relative to the crankshaft and piston to vary the compression ratio.

The gear ring may incorporate a resilient bushing to accommodate oscillatory motion between the gear ring and the cylinder, in which case the degree of oscillatory motion may be limited by a lug on the gear ring engageable with clearance in a recess in the cylinder, or by a lug on the cylinder engageable with clearance in a recess in the gearing.

According to a second aspect of the invention there is provided a rotary cylinder valve reciprocating piston internal combustion engine, having a crankshaft and a transmission drive to drivingly connect the crankshaft to the rotary cylinder, the axis of the cylinder being at an angle to the axis of the crankshaft, the transmission drive including a gear train having at least a first gear rotationally fast on the crankshaft, and a second gear rotationally fast on the rotary cylinder, wherein the transmission drive incorporates a drive cushioning element.

Preferably, the drive cushioning element is incorporated in the said first gear and may include one or more coil springs or a resilient bush.

According to another aspect of the present invention there is provided a rotary cylinder valve, reciprocating piston, internal combustion engine, having a crankshaft and a transmission drive to drivingly connect the crankshaft to the rotary cylinder, the axis of the cylinder being at an angle to the axis of the crankshaft, the transmission drive including a gear train having a first gear rotationally fast on the crankshaft, a second gear rotationally fast on the rotary cylinder, wherein one of the gears comprises a pair of coaxial gears mounted so as to enable a predetermined degree of relative rotational movement therebetween, with an anti-backlash mechanism between the said pair of gears.

Preferably, the anti-backlash mechanism is in the form of a resilient spring device which biases the two axial gears in the opposite rotational direction.

According to another aspect of the present invention there is provided a rotary cylinder valve reciprocating piston internal combustion engine wherein the rotary cylinder is closed at one end to form a combustion chamber between the closed end and the piston, wherein the rotary cylinder has a cooling volume at the closed end adjacent to the combustion chamber through which volume a cooling fluid flows, the cooling volume having at least two radially spaced galleries in fluid communication.

Preferably, adjacent galleries are in a fluid communication through passages extending between the galleries at spaced intervals, the passages being adapted to direct the fluid through the galleries in a generally circumferential direction. When three or more galleries are provided, the passages between two of the galleries are offset relative to passages between said two of the galleries and adjacent further galleries, the passages being adapted to direct the fluid through the galleries in a generally circumferential direction.

According to a further aspect of the present invention there is provided a rotary cylinder valve reciprocating piston internal combustion engine wherein the rotary cylinder is closed at one end by a wall to form a combustion chamber between the closed end and the piston, wherein the rotary cylinder has a cooling volume at said closed end through which a cooling fluid flows, wherein the fluid is directed downwardly onto said closed end, then across the wall defining the closed end and then to an exit extending away from the wall.

Preferably, the cooling volume has radially inner and outer zones defined by a dividing wall extending generally around and adjacent to the periphery of the volume and downwardly towards the wall forming the closed end of the cylinder to a position adjacent but spaced from the wall so as to provide a small gap through which fluid can flow from one zone to the other zone before passing to the exit. In this case, the dividing wall is preferably essentially a circumferential wall co-axial with the cylinder to define the outer zone as a radial chamber extending around the periphery of the closed end of the chamber.

Preferred embodiments of the present invention will now be described by way of example, with reference to the accompanying drawings in which:—

FIG. 1 shows a side view of a rotary cylinder valve internal combustion engine having a transmission drive train,

FIG. 2 shows a front view of the engine illustrated in FIG. 1,

FIGS. 3A, 3B, and 3C show a cushioning drive element in the transmission,

FIGS. 4A, 4B, 4C and 4D show an anti backlash mechanism of the drive train,

FIG. 5 shows a cross-section through the engine,

FIGS. 6A to 6F show viewers of a cooling circuit for the engine,

FIGS. 7 and 8 show, respectively, a side sectional view and a sectional plan view of an alternative cooling arrangement,

Referring now to FIGS. 1 and 2 of the drawings, there is shown a single cylinder rotary cylinder valve reciprocating piston internal combustion engine, of the type disclosed in the aforementioned PCT patent specifications. In this embodiment, the rotary cylinder 1 is driven by the crankshaft 2 through a gear train 3 which consists of a first gear 4 rotationally fast on the crankshaft 2, an idler gear 5 rotatably mounted in the engine housing 6, the idler gear 5 having rotationally fast therewith a face gear 7 which meshes with a ring gear 8 rotationally fast on the cylinder 1. Although in the present embodiment, the face gear 7 is a separate gear secured to the idler gear 5, the term rotationally fast is intended to cover an arrangement where the face gear and the idler gear are integrally formed. The first gear 4 and the idler gear 5 have straight cut teeth in this embodiment. The face gear 7 has straight cut teeth adapted to mesh with spur teeth on the ring gear 8 on the cylinder 1. The axis of rotation of the cylinder is at right angles to the axis of rotation of the crankshaft.

Referring now also to FIGS. 3A, 3B and 3C, these figures show, respectively, a front view of the first gear 4 which is mounted on the crankshaft 2 so as to rotate with the crankshaft about the main axis of the crankshaft, a plan view of FIG. 3A and an exploded perspective view of the first gear 4. The gear 4 consists of a gear wheel 10 which is resiliently mounted through a cushioning arrangement on a hub 9 which in turn is fastened securely on the crankshaft 2. The hub 9 carries four radially extending equi-distantly spaced planar locating elements 11 which are adapted to engage in corresponding slots 12 in the gear wheel 10 so that the gear is able to move rotationally relative to the hub but is constrained against axial movement. The gear wheel 10 has, between adjacent slots 12, recesses 13 each adapted to receive an associated coil spring 14. Each coil spring 14 is held in position between adjacent locating elements 11 by the edges 15 of the locating elements 11 which enter the open end of the coil 14. When installed, the ends of the coil springs also abut the edges 16 of the recesses 13 in the gear wheel. Finally, an annular clamping plate 17 is riveted to the gear wheel 10 so as to retain the springs 14 in position. In operation, the gear wheel 10 is able to oscillate relative to the hub 9 against the resistance of the springs 14. The range of movement possible is limited in each direction by the springs becoming spring bound between the edges 16 of the recesses 13 in the gearwheel and the edges 15 of the locating elements 11.

The idler gear 5 is shown in greater detail in FIGS. 1, 2, and FIGS. 4A to 4D. The gear 5 carries rotationally fast therewith, a balance weight 18 which is designed to compensate primary out of balance forces of the engine. Since the idler gear 5 rotates in the opposite sense to the crankshaft 2, it provides the necessary contra-rotating balance force. To achieve this the first gear 4 mounted on the crankshaft and the idler gear 5 have the same number of teeth.

As shown particularly in FIG. 2 and FIG. 4B, the idler gear 5 and the face gear 7 are integrally formed but in alternative embodiments it is possible for the face gear 7 to be mounted on the idler gear through a cushioning mechanism which may be in the form of a resilient bush or a wave spring. In such an arrangement, the face gear 7 may be mounted on a splined hub of the idler gear. As shown particularly in FIG. 4D, the idler gear incorporates an anti-backlash mechanism which consists of a pair of coaxial gears 20, 21 biased relative to each other in opposite rotational directions by a spring arrangement. A first one 20 of the coaxial gears includes a hub 19 by which the idler gear 5 is rotationally mounted in the engine housing. The second 21 of the coaxial gears is substantially thinner in the axial direction than the first gear and is mounted on the hub 19 so as to be rotational relative to the first gear 20. The second gear 21 is retained in axial abutting relationship with the first gear by means of a split ring located in a groove in the hub 19. The face gear 7 is located on the first gear 20 on the opposite side to the second gear 21.

Attention is also directed towards FIGS. 4A and 4B, which show details of the spring arrangement. Each of the coaxial gears 20, 21 has two tangentially disposed elongate slots 22 located on opposite sides of the axis of rotation of the gears. The slots in the two gears are aligned so as to accommodate a coil tension spring 23. In each slot 22, one end of the tension spring 23 is fastened to the gear 20 and the other end to the gear 21 so as to bias the springs, relative to each other, in the opposite rotational direction. In normal operation of the engine, the drive from the crankshaft 2 to the cylinder 1 is transmitted through the year 20 and the face gear 7. In the tooth engagement of the gears there is in practice a small clearance behind the driving tooth as it engages and drives the engaged gear. When the force of the driving transmission is reversed, which will occur during each combustion cycle as the crankshaft forces reverse between the compression and expansion strokes, the driving tooth on gear 20 leaves the abutting face of the driven tooth and then abuts the other face of the tooth because of the reversal of driving forces. This leads to a degree of noise or chattering between the teeth. This problem is solved by the present arrangement since the gear 21 is biased to engage the other face of the teeth being driven. Thus, when the drive direction is reversed, the drive is cushioned by the springs 23 acting through the gear 21 whilst the main drive gear 20 moves to contact the said other face of the tooth.

As shown in this embodiment, the spur gear on the cylinder consists of a ring gear which is a force fit or a heat shrink fit on the cylinder. In an alternative form, the spur gear may be formed in the wall of the cylinder itself. In yet another embodiment, the ring gear may incorporate a resilient bush to act as a cushioning device. In such an embodiment, the ring gear would have an inner annular steel sleeve adapted to be a force fit on the cylinder and an outer ring gear with a resilient bush located between the sleeve and the ring gear to which the sleeve and ring gear are bonded.

Referring now to FIG. 5 and FIGS. 6A-6F, there is shown a preferred cooling system for a rotary cylinder internal combustion engine, the relevant parts of which are shown in cross section in FIG. 5. The preferred cooling medium is the lubricating oil of the engine but it could alternatively be water, glycol or the like. As shown in FIG. 5, the engine has a rotary cylinder 1 containing a reciprocating piston 24. The rotary cylinder 1 has a closed end 25 to define a combustion chamber 26 between the piston and a closed wall. A centrally disposed sparking plug 27 is used to ignite the fuel which enters and leaves the combustion chamber through a valve port 28 (see FIG. 6A) in the cylinder 2. The closed end 25 of the cylinder 2 contains a cooling volume in the form of concentric galleries 29, which are circular or part-circular in plan view, as shown particularly in FIGS. 6D to 6F. The inlet port 28 is located partially in the closed end 25 of the cylinder and in this region, as shown particularly in FIG. 6A, the galleries are much shallower as shown as references 29′ and 30′. The objective of the design of the galleries is to ensure that the cooling fluid get as close as possible to the combustion chamber whilst still maintaining sufficient wall thickness to ensure reliability of the integrity of the cylinder when subject to the forces of combustion.

As shown particularly in the cross sections of the cylinder in FIGS. 6C to 6F, the concentric rings are joined by passages 31 which are offset with respect to passages 32 and 33 which constitute, respectively, and in the passage and an outfit passage for the cooling fluid. In this way, the cooling fluid is constrained to follow a generally circumferential path to ensure that an adequate volume of cooling fluid flows over the combustion chamber. Although two concentric galleries are illustrated, it will be understood that three or more may be provided. Although shown as concentric, it is not essential that they should be so arranged whilst the galleries may have a non-uniform shape in plan view depending upon the precise cooling requirements of different parts of the closed end of the cylinder.

The cooling volume in the closed end of the cylinder is in fluid communications through a port 34 (FIG. 6A) with axial cooling passages 35 extending axially along the length of the cylinder. In this way, cooling fluid, when in the form of engine lubricating oil, pumped into the cooling volume in the closed end of the cylinder, is returned to the engine sump or to a catch tank from where it is pumped to a reservoir, when a dry sump engine is used, which is typically the case for the aeroplane engines. In a preferred embodiment, the cylinder has two contiguous, concentric cylinder parts 36 and 37 with the axial cooling passages 35 being formed by axially extending grooves formed in the outer surface of the inner cylinder part 36 and closed by the inner surface of the outer cylinder part 37. As shown, the grooves are equi-distantly spaced about the circumference but need not necessarily be so.

An alternative form of cooling is shown in FIGS. 7 and 8. FIG. 7 shows a cross sectional view of a rotary cylinder internal combustion engine, similar to the view of FIG. 5, with FIG. 8 illustrating a cross section along the line W-W of FIG. 7. In this embodiment, the cooling volume consists of a radially outer zone 38 and a radially inner zone 39 each comprising a plurality of circumferentially aligned axially extending bores 38 a and 39 a respectively defined by a depending generally annular wall 40, which extends downwardly to define the two zones and terminates adjacent the wall of the closed end of the cylinder so as to provide a small gap 41 between the lower end of the annular wall 40 and the wall surface defining the combustion chamber 26. The outer zone 38 thus provides an annular chamber extending around the periphery of the cylinder 1. In this way, cooling medium can be pumped downwardly from a supply chamber 42 through the inner zone 39, from where it passes through the gap 41 and up into the outer zone 38 from where it passes upwardly to an outlet 43 and into the passages 35 in the cylinder wall. The direction of fluid flow could be reversed to suit particular engine requirements. In a simple system where the heat to be removed is not substantial, it is possible to dispense with the cooling passages 35 in the cylinder wall. 

1. A rotary cylinder valve, reciprocating piston, internal combustion engine, having a crankshaft and a transmission drive to drivingly connect the crankshaft to the rotary cylinder, the axis of the cylinder being at an angle to the axis of the crankshaft, the transmission drive including a gear train having a first gear rotationally fast on the crankshaft, a second gear rotationally fast on the rotary cylinder and an idler gear to transmit drive between the first and second gears, wherein the idler gear has a further gear rotationally fast thereto, the further gear comprising an axially extending face gear adapted to mesh with a spur gear on the rotary cylinder.
 2. An engine according to claim 1 wherein said angle is a right angle.
 3. An engine according to claim 1 or 2, wherein a balance weight is integrally formed in the idler gear, the balance weight thereby contra-rotating relative to the direction of rotation of the crankshaft.
 4. An engine according to claim 1 wherein a balance weight is secured to the idler gear in a rotationally fast manner the balance weight thereby contra-rotating relative to the direction of rotation of the crankshaft.
 5. An engine according to any one of the preceding claims wherein the first gear and the idler gear have straight cut gear teeth.
 6. An engine according to any one of claims 1 to 5, wherein the first gear and the idler gear have helical cut gear teeth.
 7. An engine according to any one of claims 1 to 5, wherein the first gear and the idler gear have bevel cut gear teeth.
 8. An engine according to any one of the preceding claims, wherein the spur gear is formed in the rotary cylinder.
 9. An engine according to any one of claims 1 to 7, wherein the spur gear is a gear ring mounted on the rotary cylinder.
 10. An engine according to claim 9 wherein the spur gear ring is shrunk on to the rotary cylinder.
 11. An engine according to any one of claims 9 or 10, wherein the gear ring incorporates a resilient bushing to accommodate oscillatory motion between the gear ring and the cylinder.
 12. An engine according to claim 11 wherein the degree of oscillatory motion is limited by a lug on the gear ring engageable with clearance in a recess in the cylinder, or by a lug on the cylinder engageable with clearance in a recess in the gearing.
 13. An engine according to claim 12 wherein said clearance incorporates resilient material.
 14. A rotary cylinder valve reciprocating piston internal combustion engine, having a crankshaft and a transmission drive to drivingly connect the crankshaft to the rotary cylinder, the axis of the cylinder being at an angle to the axis of the crankshaft, the transmission drive including a gear train having at least a first gear rotationally fast on the crankshaft, and a second gear rotationally fast on the rotary cylinder, wherein the transmission drive incorporates a drive cushioning element.
 15. An engine according to claim 14, wherein the drive cushioning element is incorporated in the said first gear.
 16. An engine according to claim 14 or 15 wherein the cushioning element includes one or more coil springs.
 17. An engine according to claim 14 or 15 wherein the cushioning element comprises a resilient bush.
 18. An engine according to any one of the preceding claims, wherein the idler gear is mounted in an engine housing so that its axis of rotation is adjustable towards and away from the axis of rotation of the crankshaft and/or the rotary cylinder.
 19. An engine according to any one of the preceding claims, wherein the face gear of the idler gear is adjustable axially towards and away from the spur gear on the rotary cylinder.
 20. An engine according to any one of the preceding claims wherein the gear interface meshing between the idler gear and the rotary cylinder is such that the cylinder is movable relative to the idler gear in a plane at right angles to the axis of rotation of the idler gear whilst still maintaining said meshing.
 21. An engine according to any one of the preceding claims claim, wherein the face gear is adjustable axially relative to the idler gear.
 22. An engine according to any one of the preceding claims, wherein a drive cushioning device is located between the face gear and the idler gear.
 23. An engine according to claim 22, wherein the drive cushioning device comprises a resilient bush or wave spring.
 24. A rotary cylinder valve, reciprocating piston, internal combustion engine, having a crankshaft and a transmission drive to drivingly connect the crankshaft to the rotary cylinder, the axis of the cylinder being at an angle to the axis of the crankshaft, the transmission drive including a gear train having a first gear rotationally fast on the crankshaft, a second gear rotationally fast on the rotary cylinder, wherein one of the gears comprises a pair of coaxial gears mounted so as to enable a predetermined degree of relative rotational movement therebetween, with an anti-backlash mechanism between the said pair of gears.
 25. An engine according to claim 24, wherein the anti-backlash mechanism is in the form of a resilient spring device which biases the two axial gears in the opposite rotational direction.
 26. A rotary cylinder valve reciprocating piston internal combustion engine wherein the rotary cylinder is closed at one end to form a combustion chamber between the closed end and the piston, wherein the rotary cylinder has a cooling volume at the closed end adjacent to the combustion chamber through which volume a cooling fluid flows, the cooling volume having at least two radially spaced galleries in fluid communication.
 27. An engine according to claim 26 wherein the galleries are generally circular or part circular.
 28. An engine according to claim 26 or 27 wherein the galleries are concentric and have a common axis.
 29. An engine according to claim 28, wherein the common axis is the axis of the cylinder.
 30. An engine according to claims 26 or 27, wherein the galleries have spaced axes.
 31. An engine according to any one of claims 26 to 30 wherein adjacent galleries are in a fluid communication through passages extending between the galleries at spaced intervals, the passages being adapted to direct the fluid through the galleries in a generally circumferential direction.
 32. An engine according to any one of claims 26 to 31, wherein when three or more galleries are provided, the passages between two of the galleries are offset relative to passages between said two of the galleries and adjacent further galleries, the passages being adapted to direct the fluid through the galleries in a generally circumferential direction.
 33. An engine according to claim 26 wherein the cooling volume further includes cooling passages in the cylinder wall extending from said cooling volume towards the other end of the cylinder, the cylinder being formed by two contiguous concentric cylindrical parts, one of which has a plurality of grooves in its interfacing wall surface to thereby form said passages between the two cylinder parts.
 34. A rotary cylinder valve reciprocating piston internal combustion engine wherein the rotary cylinder is closed at one end by a wall to form a combustion chamber between the closed end and the piston, wherein the rotary cylinder has a cooling volume at said closed end through which a cooling fluid flows, wherein the fluid is directed downwardly onto said closed end, then across the wall defining the closed end and then to an exit extending away from the wall.
 35. An engine according to claim 34, wherein the cooling volume has radially inner and outer zones defined by a dividing wall extending generally around and adjacent to the periphery of the volume and downwardly towards the wall forming the closed end of the cylinder to a position adjacent but spaced from the wall so as to provide a small gap through which fluid can flow from one zone to the other zone before passing to the exit.
 36. An engine according to claim 35 wherein the dividing wall is essentially a circumferential wall co-axial with the cylinder to define the outer zone as a radial chamber extending around the periphery of the closed end of the chamber.
 37. An engine as claimed in the combination of any two or more of claims 1, 14, 24, 26, or
 34. 